Engine won't shut off

[howesdivin]

I have a 1999 AQ 225 Explorer with the original Johnson 225 OB.  The engine will not shut off with the key switch.  I replaced the key switch and the same thing.

Any ideas on where to start troubleshooting?

Thanks.

[wingtime]

Might have a break in the ground or the mag cut off lead (black w yellow trace). Also be sure to buy a genuine switch. Also could be an issue in the MOB curcuit.

[boatnamesue]

I'm not familiar with Johnson OBs.  But with yamaha, I'd tell you to check the ground wire between the ignition harness and ignition switch.  You could also do a voltage drop test on the ignition harness, from engine side to ignition side.  The second step would be to check the ground at the cdi, or likewise johnson system.